Animal & Avian Sciences

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Adaptation of A/Mallard/Potsdam/178-4/83 (H2N2) in Japanese quail leads to Replication and Transmission in Chickens
(2005-05-02) Sorrell, Erin Maureen; Perez, Daniel R; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Influenza is a single stranded, negative-sense RNA virus with a segmented genome that can infect avian and mammalian species. Influenza viruses from the avian reservoir do not seem to replicate efficiently in humans upon direct transmission. Therefore, an intermediate host is involved in generating mutations to create a more transmissible or an avian-human reassortant virus. Quail have been highlighted as a potential reservoir and intermediate host of avian influenza. To assess the potential of quail as an intermediate host, A/Mallard/Postdam/178-4/83, H2N2 was tested to determine if through adaptation in quail a mallard strain can replicate and transmit in quail, as well as other avian species. After six serial passages of lung homogenate a virus arose, which replicated and transmitted directly to contact quail. When chickens were infected with this quail-adapted virus replication and transmission were observed, while no replication was noted in the chickens infected with wild type H2N2 virus.
Allele-Specific Expression of CD4+ T Cells in Response to Marek’s Disease Virus Infection
(MDPI, 2019-09-17) Bai, Hao; He, Yanghua; Ding, Yi; Carrillo, José A.; Selvaraj, Ramesh K.; Zhang, Huanmin; Chen, Jilan; Song, Jiuzhou
Marek’s disease (MD) is a T cell lymphoma disease induced by Marek’s disease virus (MDV), a highly oncogenic α herpesvirus primarily affecting chickens. MD is a chronic infectious disease that threatens the poultry industry. However, the mechanisms of genetic resistance for MD are complex and not completely understood. In this study, to identify high-confidence candidate genes of MD genetic resistance, high throughput sequencing (RNA-seq) was used to obtain transcriptomic data of CD4+ T cells isolated from MDV-infected and non-infected groups of two reciprocal crosses of individuals mating by two highly inbred chicken lines (63 MD-resistant and 72 MD-susceptible). After RNA-seq analysis with two biological replicates in each group, we identified 61 and 123 single nucleotide polymorphisms (SNPs) (false discovery rate (FDR) < 0.05) annotated in 39 and 132 genes in intercrosses 63 × 72 and 72 × 63, respectively, which exhibited allele-specific expression (ASE) in response to MDV infection. Similarly, we identified 62 and 79 SNPs annotated in 66 and 96 genes in infected and non-infected groups, respectively. We identified 534 and 1543 differentially expressed genes (DEGs) (FDR < 0.05) related to MDV infection in intercrosses 63 × 72 and 72 × 63, respectively. We also identified 328 and 20 DEGs in infected and non-infected groups, respectively. The qRT-PCR using seven DEGs further verified our results of RNA-seq analysis. The qRT-PCR of 11 important ASE genes was performed for gene functional validation in CD4+ T cells and tumors. Combining the analyses, six genes (MCL1, SLC43A2, PDE3B, ADAM33, BLB1, and DMB2), especially MCL1, were highlighted as the candidate genes with the potential to be involved in MDV infection. Gene-set enrichment analysis revealed that many ASE genes are linked to T cell activation, T cell receptor (TCR), B cell receptor (BCR), ERK/MAPK, and PI3K/AKT-mTOR signaling pathways, which play potentially important roles in MDV infection. Our approach underlines the importance of comprehensive functional studies for gaining valuable biological insight into the genetic factors behind MD and other complex traits, and our findings provide additional insights into the mechanisms of MD and disease resistance breeding in poultry.
Analyses of inter-individual variations of sperm DNA methylation and their potential implications in cattle
(Springer Nature, 2019-11-21) Liu, Shuli; Fang, Lingzhao; Zhou, Yang; Santos, Daniel J.A.; Xiang, Ruidong; Daetwyler, Hans D.; Chamberlain, Amanda J.; Cole, John B.; Li, Cong-jun; Yu, Ying; Ma, Li; Zhang, Shengli; Liu, George E.
DNA methylation has been shown to be involved in many biological processes, including X chromosome inactivation in females, paternal genomic imprinting, and others.
Analysis of recent segmental duplications in the bovine genome
(Springer Nature, 2009-12-01) Liu, George E; Ventura, Mario; Cellamare, Angelo; Chen, Lin; Cheng, Ze; Zhu, Bin; Li, Congjun; Song, Jiuzhou; Eichler, Evan E
Duplicated sequences are an important source of gene innovation and structural variation within mammalian genomes. We performed the first systematic and genome-wide analysis of segmental duplications in the modern domesticated cattle (Bos taurus). Using two distinct computational analyses, we estimated that 3.1% (94.4 Mb) of the bovine genome consists of recently duplicated sequences (≥ 1 kb in length, ≥ 90% sequence identity). Similar to other mammalian draft assemblies, almost half (47% of 94.4 Mb) of these sequences have not been assigned to cattle chromosomes. In this study, we provide the first experimental validation large duplications and briefly compared their distribution on two independent bovine genome assemblies using fluorescent in situ hybridization (FISH). Our analyses suggest that the (75-90%) of segmental duplications are organized into local tandem duplication clusters. Along with rodents and carnivores, these results now confidently establish tandem duplications as the most likely mammalian archetypical organization, in contrast to humans and great ape species which show a preponderance of interspersed duplications. A cross-species survey of duplicated genes and gene families indicated that duplication, positive selection and gene conversion have shaped primates, rodents, carnivores and ruminants to different degrees for their speciation and adaptation. We identified that bovine segmental duplications corresponding to genes are significantly enriched for specific biological functions such as immunity, digestion, lactation and reproduction. Our results suggest that in most mammalian lineages segmental duplications are organized in a tandem configuration. Segmental duplications remain problematic for genome and assembly and we highlight genic regions that require higher quality sequence characterization. This study provides insights into mammalian genome evolution and generates a valuable resource for cattle genomics research.
Analysis of the fecal microbiota of fast- and slow-growing rainbow trout (Oncorhynchus mykiss)
(Springer Nature, 2019-10-29) Chapagain, Pratima; Arivett, Brock; Cleveland, Beth M.; Walker, Donald M.; Salem, Mohamed
Diverse microbial communities colonizing the intestine of fish contribute to their growth, digestion, nutrition, and immune function. We hypothesized that fecal samples representing the gut microbiota of rainbow trout could be associated with differential growth rates observed in fish breeding programs. If true, harnessing the functionality of this microbiota can improve the profitability of aquaculture. The first objective of this study was to test this hypothesis if gut microbiota is associated with fish growth rate (body weight). Four full-sibling families were stocked in the same tank and fed an identical diet. Two fast-growing and two slow-growing fish were selected from each family for 16S rRNA microbiota profiling.
ANALYSIS OF THE ROLE OF PRDM14 IN PLURIPOTENCY AND SPECIFICATION OF THE GERM CELL NICHE IN THE DOMESTIC PIG
(2018) Sandmaier, Shelley; Telugu, Bhanu; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The generation of functional, mature germ cells in order to pass on its genetic information to the next generation is of paramount importance to a species’ survival. As a result, primordial germ cells (PGC), the precursor cells that give rise to mature spermatozoa or oocytes, are one of the first cell types to be specified and induced in the early mammalian embryo. In mammals, this process happens during the primitive streak stage of development and PGCs continue to proliferate as they migrate from the posterior end of the embryo through the hindgut and settle in the future gonadal region. One gene in particular, PRDM14, is required for PGC specification in the mouse, but its function was unknown in the domestic pig (Sus scrofa). This dissertation project sought to determine the role of PRDM14 in the porcine germ cell program as well as in early embryo development. The first study used the mouse as a model using CRISPR/Cas9 technology to direct pluripotent stem cells toward the germ cell pathway by aggregation with a host embryo that was unable to form PGCs. Chimeras generated by this technique exhibited 100% occupation of the germline by donor control stem cells. In the second study, mRNA transcripts for a suite of germ cell-related genes were analyzed to determine their expression in various stages of the early porcine embryo: from zygote to blastocyst and embryonic day 28. Unlike in the mouse and human systems, several genes that were predicted to be expressed in the early embryo (PRDM14, TET1, and PRDM1, among others) were found to be extremely low in abundance. In the final study, the function of PRDM14 in the pig was disrupted using gene editing, and the resulting phenotype was characterized. Loss of PRDM14 does not seem to be critical for the specification of PGCs in the domestic pig, as evidenced by the existence of germ cells following knockout. Together, these studies have applications for spermatogonial stem cell transplantation technology in order to expand the genetic reach of superior animals by producing animals whose germ cells are derived from a genetically valuable donor.
ANTAGONISTIC MECHANISM OF METABOLITES FROM LACTOBACILLUS CASEI AGAINST FOODBORNE ENTEROHEMORRHAGIC ESCHERICHIA COLI
(2022) Aditya, Arpita; Biswas, Debabrata; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Enterohemorrhagic Escherichia coli O157: H7 (EHEC), a foodborne enteropathogen, remains a significant public health concern since its discovery in 1982. With an incredibly low infectious dose (10-100 bacteria), this pathogen can cause self-limiting diarrhea, vomiting, and abdominal cramps. However, more complicated disease conditions such as bloody diarrhea or hemolytic colitis have been known to develop depending on the serotype involved in the infection, and on immune status and/or age of the patients. Due to its Shiga toxin (Stx) production ability, EHEC infection may lead to a kidney-related problem known as hemolytic uremic syndrome (HUS), which requires advanced medical care. Unlike other bacterial illnesses, therapeutic administration of antibiotics to treat EHEC infections is not recommended due to their controversial association with Stx production. As a result, only preventative/prophylactic and immune-supportive strategies are followed for EHEC infections. Using the antibacterial properties of probiotic bacteria and the metabolites they produce are promising alternative strategies for preventing EHEC infections. We have targeted the probiotic bacteria Lactobacillus casei to determine the mechanism of this alternative strategy. In our study, we have executed microbiological, molecular, chromatographic, and metagenomic approaches to determine the antagonistic mechanisms of action of their metabolites, specifically conjugated linoleic acid (CLA) produced by Lactobacillus casei, against the growth and metabolism of EHEC. The metabolites of wild-type L. casei (LCwt) were augmented by supplementing it with a prebiotic-like dietary component, namely peanut flour (PF) (LCwt+PF), while another LCwt was also genetically engineered (LCCLA) to over convert CLA from linoleic acid (LA). These modifications showed effective results in controlling EHEC both in vitro and in ex vivo conditions. Total metabolites present in cell-free culture supernatant (CFCS) of LCwt, LCwt+PF, and LCCLA were able to control the growth of EHEC without negatively hampering the relative abundance of Firmicutes and Bacteroidetes present in rumen fluid (RF). Among these CFCSs, CFCSCLA exerted the most desirable outcome by eliminating EHEC. In vitro studies demonstrated that, a lower concentration of purified CLA worked synergistically with other metabolites of LCwt and augmented their inhibitory activity against EHEC. The orchestrated effect of metabolites has been observed to downregulate the virulence genes, disrupt the cell membrane, interfere with cell division, and damage their genomic DNA. The probable effect of these metabolites, specifically CLA, on Stx production and neutralization was also investigated by assessing host cell cytotoxicity. Total metabolites of Lactobacillus spp. as well as CLA itself, showed improvement in cell survivability when exposed to Stx. Our findings established a ground to explore the effect of specific metabolites obtained from probiotic bacteria in control and prevention of EHEC. The findings also showed a promising association of purified CLA in neutralizing Stx which can be further explored to use it in therapeutic purposes.
ANTIBIOTIC ALTERNATIVES FOR TREATMENT OF MASTITIS IN DAIRY CATTLE
(2019) Scholte, Cynthia Madeleine; Moyes, Kasey M; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Mastitis is one of the most costly diseases to the dairy cow industry. Implementation of management protocols have decreased the incidence rate of contagious mastitis pathogens, while the incidence of cases caused by environmental pathogens, such as Escherichia coli (E. coli) and Streptococcus uberis (Strep. uberis), remains unchanged. Currently, antibiotics are the primary therapy utilized to control mastitis. However, growing concern for antibiotic overuse, improper use and bacterial resistance have led to the examination of alternative strategies. Two promising alternative mitigation strategies were explored in the research leading to this dissertation. The first is a potent endolysin, PlyC, which has demonstrated bactericidal activity against several streptococcal species in a variety of applications. However, it is unknown how PlyC interacts with the bovine immune system. Varying doses of PlyC were non-toxic and did not alter the oxidative burst response of bovine neutrophils, the first immune cells recruited to the intramammary infection. The second alternative to an antimicrobial drug explored was citrus oil dissolved in ethanol. This was tested against E. coli strain P4. Prior antimicrobial investigations with citrus oil utilized dimethylsulfoxide as a carrier solvent, which is currently prohibited in the dairy industry. Citrus oil and its primary components were tested to determine minimum inhibitory, bactericidal and biofilm eradication concentrations. Citrus oil components, citral and linalool, demonstrated better antimicrobial activity than the native oil in vitro. In addition, citral and linalool were minimally toxic to bovine neutrophils and did not hinder their oxidative burst response in vitro. Because citral demonstrated greater antimicrobial activity than linalool, it was the logical candidate to test for the efficacy as an intramammary therapy against experimentally-induced E. coli mastitis. Unfortunately, citral treatment did not differ from a common intramammary antibiotic therapy or sterile buffered solution. In conclusion, the use of PlyC as an alternative therapy for Strep. uberis mastitis is promising as PlyC may not interfere with immune response during mastitis. The antimicrobial effects of citral may better serve as a disinfectant than a therapy for E. coli mastitis.
Antimicrobial Effect and Probiotic Potential of Phage Resistant Lactobacillus plantarum and its Interactions with Zoonotic Bacterial Pathogens
(MDPI, 2019-06-05) Nagarajan, Vinod; Peng, Mengfei; Tabashsum, Zajeba; Salaheen, Serajus; Padilla, Joselyn; Biswas, Debabrata
Development of phage-resistant probiotic particularly Lactobacillus is an alternative approach to enhance their beneficial effects as in animal feed supplements. In this study, we developed phage-resistant Lactobacillus plantarum (LP+PR) mutant and compared their antimicrobial effects and probiotic potential against zoonotic bacterial pathogens including Salmonella enterica serovar Typhimurium, enterohemorrhagic Escherichia coli (EHEC), Staphylococcus aureus, and Listeria monocytogenes with phage-sensitive L. plantarum (LP) strain. LP+PR strain showed markedly higher growth rate than wild-type LP strain. In co-culture with LP+PR and in the presence of cell-free cultural supernatants (CFCSs) of LP+PR, the growth of S. Typhimurium, EHEC, S. aureus, and L. monocytogenes were reduced significantly (P < 0.05). The adhesion ability of LP+PR was slightly higher than the LP on human epithelial INT-407 cells. Most importantly, LP+PR strain significantly inhibited the adhesive and invasive abilities of all four zoonotic pathogens to INT-407 cells (P < 0.05). Moreover, real-time qPCR revealed that in the presence of LP+PR strain or its CFCSs, expression of virulence genes of these zoonotic bacterial pathogens were suppressed significantly (P < 0.05). These findings suggest that the LP+PR strain is capable of inhibiting major zoonotic bacterial pathogens efficiently and would be a potential candidate for industrial usage in animal production or fermentation.
Application of orange essential oil as an antistaphylococcal agent in a dressing model
(Springer Nature, 2012-08-16) Muthaiyan, Arunachalam; Biswas, Debabrata; Crandall, Philip G; Wilkinson, Brian J; Ricke, Steven C
Staphylococcus aureus is the pathogen most often and prevalently involved in skin and soft tissue infections. In recent decades outbreaks of methicillin-resistant S. aureus (MRSA) have created major problems for skin therapy, and burn and wound care units. Topical antimicrobials are most important component of wound infection therapy. Alternative therapies are being sought for treatment of MRSA and one area of interest is the use of essential oils. With the increasing interest in the use and application of natural products, we screened the potential application of terpeneless cold pressed Valencia orange oil (CPV) for topical therapy against MRSA using an in vitro dressing model and skin keratinocyte cell culture model. The inhibitory effect of CPV was determined by disc diffusion vapor assay for MRSA and vancomycin intermediate-resistant S. aureus (VISA) strains. Antistaphylococcal effect of CPV in an in vitro dressing model was tested on S. aureus inoculated tryptic soya agar plate. Bactericidal effect of CPV on MRSA and VISA infected keratinocyte cells was examined by enumeration of extra- and intra-cellular bacterial cells at different treatment time points. Cytotoxic effects on human skin cells was tested by adding CPV to the keratinocyte (HEK001) cells grown in serum free KSFM media, and observed by phase-contrast microscope. CPV vapour effectively inhibited the MRSA and VISA strains in both disc diffusion vapour assay and in vitro dressing model. Compared to untreated control addition of 0.1% CPV to MRSA infected keratinocyte decreased the viable MRSA cells by 2 log CFU/mL in 1 h and in VISA strain 3 log CFU/mL reduction was observed in 1 h. After 3 h viable S. aureus cells were not detected in the 0.2% CPV treatment. Bactericidal concentration of CPV did not show any cytotoxic effect on the human skin keratinocyte cells in vitro. At lower concentration addition of CPV to keratinocytes infected with MRSA and VISA rapidly killed the bacterial cells without causing any toxic effect to the keratinocytes. Therefore, the results of this study warrant further in vivo study to evaluate the potential of CPV as a topical antistaphylococcal agent.
Are CD45RO+ and CD45RA- genuine markers for bovine memory T cells?
(Springer Nature, 2022-10-11) Anmol, Kandel; Akanksha, Hada; Zhengguo, Xiao
Effective vaccination induces memory T cells, which protect the host against pathogen re-infections. Therefore, detection of memory T cells is essential for evaluating vaccine efficacy, which was originally dependent on cytokine induction assays. Currently, two isoforms of CD45 tyrosine phosphatase, CD45RO expression and CD45RA exclusion (CD45RO+/ CD45RA-) are used extensively for detecting memory T cells in cattle. The CD45RO+/CD45RA- markers were first established in humans around three decades ago, and were adopted in cattle soon after. However, in the last two decades, some published data in humans have challenged the initial paradigm, and required multiple markers for identifying memory T cells. On the contrary, memory T cell detection in cattle still mostly relies on CD45RO+/CD45RA- despite some controversial evidence. In this review, we summarized the current literature to examine if CD45RO+/CD45RA- are valid markers for detecting memory T cells in cattle. It seems CD45RA and CD45RO (CD45RA/RO) as markers for identifying bovine memory T cells are questionable.
Array CGH-based detection of CNV regions and their potential association with reproduction and other economic traits in Holsteins
(Springer Nature, 2019-03-07) Liu, Mei; Fang, Lingzhao; Liu, Shuli; Pan, Michael G.; Seroussi, Eyal; Cole, John B.; Ma, Li; Chen, Hong; Liu, George E.
Copy number variations (CNVs) are structural variants consisting of large-scale insertions and deletions of genomic fragments. Exploring CNVs and estimating their effects on phenotypes are useful for genome selection but remain challenging in the livestock.
ASSESSMENT OF MALE GIANT PANDA SEASONAL REPRODUCTION, SEXUAL MATURITY AND COMPARATIVE SPERM CRYOTOLERANCE
(2010) Aitken-Palmer, Copper; Ottinger, Mary Ann; Howard, JoGayle; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The giant panda is unique as one of the most studied endangered species. Interestingly, despite this, little is known about basic male reproductive physiology. Behavioral problems have posed challenges for reproductive success in the captive population, while geographical isolation and habitat fragmentation threaten the wild population. Techniques such as sperm cryopreservation can improve genetic management and reproductive success within captive populations. But without comparative freeze-thawing studies, diverse methods used for cryopreservation result in inconsistent post-thaw quality, potentially compromising sperm quality and fertility for artificial insemination. This, compounded by limited knowledge of male reproductive physiology, has challenged conservation goals for the giant panda. Specific objectives of this study include: 1) assess the influence of season on male giant panda reproduction by determining annual changes in testis size, body size, testosterone production, sperm quality and production, and reproductive behaviors throughout the year; 2) characterize the onset of sexual maturity in the male giant panda by documenting the timing of initial sperm production, increasing testicular size and body weight, rising androgen production and initiation of reproductive behaviors; and 3) identify factors influencing giant panda sperm cryopreservation by comparing the effect of freeze-thawing on sperm motility, acrosomal integrity, forward progressive movement and longevity. Results provide evidence that 1) reproductive seasonality in the male giant panda is more protracted than the female, with coordinated increases in testes size, androgen production, sperm density, and sexual behaviors; thereby maintaining reproductive competence to prepare for, and accommodate, a brief unpredictable female estrus; 2) sexual maturity in the male giant panda is first observed with consistent sperm production at 5.5 yr, then accompanied by increasing body weight, fecal androgen concentrations, and culminating with the onset of reproductive behaviors, such as scent marking between 7.5 - 8.5 yr; and 3) the giant panda spermatozoon has the capacity to withstand cold stress applied by multiple means, specifically after freezing and thawing using a unique field friendly dry shipper approach. These data greatly improve our understanding of male giant panda reproductive physiology, specifically seasonal rhythms, the cascade of changes associated with sexual maturation, and insights into improved comparative approaches for sperm cryopreservation.
ASSOCIATION OF SINGLE NUCLEOTIDE POLYMORPHISMS WITH PHENOTYPIC PRODUCTION TRAITS IN BROILER CHICKENS
(2009) Liu, Xuan; Porter, Tom E; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
This research investigated the association between SNPs and phenotypic production traits in fat and lean chicken broiler lines. In previous research, eleven SNPs in the promoter regions of four candidate genes were selected. In this study, significant associations were detected between AKR1B10 SNP1 and SDC1 SNP1 and fat yield. SDC1 SNP1 was significantly associated with fat weight. SOD3 SNP2 was associated with breast yield. Five sire-SNP interactions and one sex-SNP interaction were significant. There was a significant interaction between sex and SDC1 SNP3 on muscle-related factor. GPC3 SNP1 interacted with time period on body weight from week 1 to week 9. QTLs on chromosomes 1, 3 and 4 for body fat were refined by incorporating these SNPs into QTL analysis. These genetic markers may be of great value for marker-assisted selection (MAS) for chickens with less abdominal fat as well as genetic markers for body fat accumulation in humans.
Avian reovirus: a furious and fast evolving pathogen
(Microbiology Society, 2023-10) Egana-Labrin, Sofia; Broadbent, Andrew J.
Avian reoviruses (ARVs) have a significant economic impact on the poultry industry, affecting commercial and backyard flocks. Spread feco-orally, or vertically, many do not cause morbidity, but pathogenic strains can contribute to several diseases, including tenosynovitis/arthritis, which is clinically the most significant. The last decade has seen a surge in cases in the US, and due to ongoing evolution, seven genotypic clusters have now been identified. Control efforts include strict biosecurity and vaccination with commercial and autogenous vaccines. Research priorities include improving understanding of pathogenesis and developing new vaccines guided by ongoing molecular and serologic surveillance.
BIOACTIVE LACTOBACILLUS CASEI IN REDUCING GROWTH AND COLONIZATION OF CAMPYLOBACTER JEJUNI
(2018) Tabashsum, Zajeba; Biswas, Debabrata; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Campylobacter jejuni (CJ) is one of the pre-dominant causative agents of acute gastroenteritis in the US and occurs commonly through handling/consumption of contaminated poultry products. Probiotics with enhanced bioactive metabolites such as conjugated linoleic acids (CLAs) play crucial role in improving host health and act as antimicrobials. Further, prebiotic like components such as bioactive phenolics from berry pomace extract (BPE) can stimulate growth of beneficial microbes including Lactobacillus casei (LC) and inhibit bacterial pathogens in vitro. In this study, we aimed to assess efficiency of CLA overproducing LC (LC+mcra) alone or in presence of BPE against CJ. LC+mcra alone or LC+mcra with BPE reduced CJ growth, adhesion and invasion efficiency to cultured cells and also altered physicochemical properties, gene expressions related to virulence. These findings suggest, BPE and LC+mcra in combination may able to prevent CJ colonization in poultry and reduce cross-contamination, hence control foodborne infections with CJ in human.
BIOLOGY AND MANAGEMENT OF REPRODUCTION IN CAPTIVE CRANES
(2017) Brown, Megan Elizabeth; Keefer, Carol L; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
There are 15 species of cranes found throughout the world, 11 of which are listed as vulnerable or endangered. All 15 species are currently managed in captivity; however, with increased threats to wild crane habitats and populations, ex situ management becomes increasingly critical as a hedge against extinction. Reproduction and the production of offspring is required to ensure self-sustaining populations managed in ex situ conservation breeding programs. However, current reproductive success of the endangered whooping crane (Grus americana), as well as other species, maintained ex situ is suboptimal and hinders population sustainability and reintroduction goals. The objectives of this dissertation were to 1) develop a cryopreservation protocol for crane semen to improve genetic management in endangered cranes, 2) investigated seasonal hormone patterns and measured the impact of captive environment on hormone production and reproductive behaviors, and 3) retrospectively examine the effect of bird as well as management variables on egg fertility in whooping cranes. The findings demonstrated that 1) sperm of both whooping and white-naped crane performed better following cryopreservation when dimethyl-sulfoxide is utilized as a cryoprotectant, 2) seasonal fluctuations occur in hormone production in both sexes, while addition of a water feature to captive enclosures stimulated reproduction in females, and 3) female specific variables had the greatest influence on probability of egg fertility. Overall findings will help whooping crane management Continued research into the mechanisms controlling sperm sensitivity to cryo-damage, egg production, and fertilization are necessary to mitigate reproductive problems in captive crane species.
Bos taurus–indicus hybridization correlates with intralocus sexual-conflict effects of PRDM9 on male and female fertility in Holstein cattle
(Springer Nature, 2019-08-28) Seroussi, Eyal; Shirak, Andrey; Gershoni, Moran; Ezra, Ephraim; Santos, Daniel Jordan de Abreu; Ma, Li; Liu, George E.
Crossover localization during meiotic recombination is mediated by the fast-evolving zinc-finger (ZnF) domain of gene PRDM9. To study its impact on dairy cattle performance, we compared its genetic variation between the relatively small Israeli (IL) Holsteins and the North American (US) Holsteins that count millions.
BOVINE NEUTROPHILS RELEASE EXTRACELLULAR TRAPS UPON STIMULATION WITH OSTERTAGIA OSTERTAGI
(2018) Mendez, Jonatan; Xiao, Zhengguo; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Ostertagia ostertagi is a widespread parasite that causes significant production losses in the cattle industry. Recently discovered neutrophil extracellular traps (NETs) have been demonstrated as important effector mechanisms of neutrophils against various pathogens including parasitic worms. Exposure of neutrophils to O. ostertagi extract resulted in a significant release of extracellular DNA and co-localization of NET associated proteins histone and neutrophil elastase confirmed these structures of DNA as NETs. In response to both live and heat-killed O. ostertagi larvae, there was a similarly strong release of NETs. O. ostertagi induced NETs were significantly diminished by inhibition of enzymes NADPH oxidase, neutrophil elastase, and myeloperoxidase. Interestingly, NETs were also released in response to non-pathogenic nematode C. elegans indicating a potential conserved response to nematodes. Mouse neutrophils demonstrated a similar NET response to O. ostertagi however there was no response to C. elegans. Surprisingly, these NET responses did not appear to be dependent on production of reactive oxygen species (ROS) as has been previously reported. This is the first report indicating O. ostertagi-induced NET formation and indicates a potential role for NETs in the response against O. ostertagi infection.
Campylobacter spp. in bulk tank milk and milk filters from US dairy farms
(2015) Del Collo, Laura P; Biswas, Debabrata; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Campylobacter spp. are a common cause of foodborne outbreaks associated with raw or unpasteurized milk, and Campylobacter spp. have also been detected on most dairies in the US. An estimate of the prevalence of thermophilic Campylobacter spp. in bulk tank milk (BTM) on US dairy operations was determined as part of the National Animal Health Monitoring System’s Dairy 2014 study. Campylobacter spp. were detected in the BTM and milk filters from 34.2% of the 234 dairies. Isolates were obtained from 18.4% of the dairies. C. jejuni was the most frequently isolated species, and this species is also the most common cause of human infection. When resistance to a panel of nine antimicrobials was tested, 68.4% of C. jejuni isolates were resistant to tetracycline. This survey suggests that BTM from US dairies can be contaminated with pathogenic Campylobacter spp., and the consumption of unpasteurized, raw milk represents a human health risk.